• The prevalence of obesity among native American children ranks with the highest in the United States. However, little is known about associated risk factors for obesity among these children. We conducted a medical record review of 261 preschool children enrolled in the Mescalero Apache tribe to determine the prevalence of obesity and associated risk factors. The prevalence of obesity (weight for height >95th percentile) in this population was 19.5%. The prevalence of obesity (body mass index >95th percentile) in their mothers was 23%. Children with obese mothers were more than twice as likely to be obese than children of nonobese mothers. Children with a high birth weight were three times as likely to be obese as children of low or normal birth weight. The high prevalence of obesity may be due to both life-style and dietary patterns on the reservation. Family-based interventions are needed to prevent obesity and its long-term consequences in this population.